This application relates to an integral reflector lamp having improved light output efficiency with better control of light output distribution, improved light source alignment, increased shock resistance, internal heat shielding and heat transfer, and more accurate yet simplified manufacturing methods.
The design of reflectors used with lamps having medium sized screw bases has not changed since the inception of incandescent parabolic lamps. Due to limitations in glass production technology, a certain size area had to be lost in the back of the reflector. These limitations included the necessity that the glass thickness be uniform over the reflector body and that draft angles allow for easy release of glass pressing tools. Points of contact for internal lead-in wires (ferrules) were placed into the glass so that the widest possible spacing was achieved to allow the use of the longest filament and bridge mechanism possible. Filaments were mounted perpendicular to the reflector axis and were made as long as possible to increase stability and shock resistance. Bases were designed to match up to the spacing of the filaments and the ferrules. When halogen capsules began to be used as internal light sources instead of the bare coil assemblies few changes were made in the reflector design to take advantage of this new technology. Assemblies employing capsules were designed to be mounted to fit the old spacings used in incandescent lamps even though the most widely used base type for operation at line voltage in the United States was the medium screw base whose design could not take advantage of such wide lead-in spacings. The area of the reflector section missing at the rear of the reflector remained the same even though such a large area was no longer required to accommodate the light source.
Methods of lamp production have also remained the same based on those used to make incandescent lamps. Internal light source alignment and filament location were controlled by referencing to the ferrules and the ends of the internal lead-in wires that contacted the ferrules. Tolerances on ferrule length and depth of insertion into the glass at the rear of the reflector were wide. Some manufacturers devised methods to focus the internal light source before the assembly was brazed into the ferrules thus adding time and cost to the manufacturing process. Due to the use of these inaccurate methods, beam intensity and beam pattern could vary greatly from lamp to lamp. In addition, such assemblies were susceptible to shock during manufacturing, shipping, or operation since the internal light source could change position and therefore change the photometric properties of the lamp. Since all capsule support was supplied through the internal lead-in wires, shock could also cause lamp failure due to breakage of welds, the internal capsule light source itself, or the filament.
U.S. Pat. No. 4,829,210 issued May 9, 1989 is directed to a reflector lamp including a light source capsule. The capsule is mounted within the neck of the lamp by a bowl shaped member which is a friction fit within the neck of the lamp. However, positioning of the lamp capsule is dependent upon the accuracy of the dimensions of the neck and positioning member which may be difficult to control in large volume manufacture. Furthermore, a friction fit is subject to loosening because of physical or thermal shocks and subsequent dimensional changes over the life of the lamp. The present invention is directed to overcoming these difficulties.
The invention disclosed here provides for easy, efficient alignment and corresponding production methods, improved lamp output efficiency and control of beam distribution, improved shock resistance, and internal heat shielding. Additional reflector surface is provided in the critical neck area of the reflector where limitations in glass pressing technology have resulted in a large hole.